It has become increasingly apparent using molecular techniques such as polymerase chain reaction (PCR) amplification of hepatitis B virus (HBV) and hepatitis C virus (HCV) genomes in serum or liver that low level persistent viral infection is a major problem in alcoholics with liver disease. There is recent evidence to suggest that chronic ethanol abuse in the setting of HBV and HCV infection promotes the deterioration of the liver disease and increases the risk for development of hepatocellular carcinoma. Thus, it is important to understand the effects of ethanol on the host cellular and humoral immune response to HBV and HCV that may allow for persistent viral infection to occur. This proposal will focus on molecular genetic techniques designed to induce a host immune response to viral structural proteins. We anticipate that such approaches may eventually be used to design antiviral agents that reduce or terminate viral replication in the liver and therefore have clinical applications for the alcoholic. Our aims are as follows: (1) Explore the use of polynucleotide based immunization to generate humoral and cellular immune responses in mice to the highly conserved HCV core protein and study the effects of ethanol on antiviral immune responses. (2) Evaluate the effect of ethanol on cellular and humoral immune responses to HBV large (LBHs) and middle (MHBs) envelope and core proteins as generated by DNA immunization. (3) Study the antiviral effects of HBV dominate negative core mutant constructs used as "intracellular immunogens" to inhibit HBV replication and examine the role of ethanol on intrahepatic viral gene expression in vivo. Indeed, it has not, heretofore, been possible to study cellular immune responses in vivo to HCV and HBV structural proteins with respect to any alcohol effects, since there was no method available to generate viral specific CTL activity in an animal model system. Our preliminary data suggests that polynucleotide based immunization will induce strong cellular immunity to HCV and HBV that may have antiviral activity. These investigations will allow us to assess ethanol effects on such cellular immune responses which will contribute to a better understanding of the pathogenesis of persistent viral infection in the alcoholic with liver disease.